This site has a great overview on the Croatian legal system.
http://brochures.wolftheiss.com/en/7uTYfh2b/croatia/
The one crucial bit relates to getting judgments for rulings. Notice how he isn't suing anyone from a country Croatia has an agreement with.
Currently, there are 16 bilateral agreements regulating and simplifying the recognition and enforcement of foreign judgments, with Algeria, Bosnia and Herzegovina, Bulgaria, Cyprus, Czech Republic, France, Greece, Hungary, Iraq, Macedonia, Mongolia, Poland, Romania, Russia, Slovenia and Turkey, and one bilateral agreement regulating and simplifying the recognition and enforcement of foreign arbitral awards with Austria
It's all absurd on so many levels.